Bearing device and turbocharger

Abstract

A bearing device includes: a bearing housing; a floating metal having a cylindrical shape and disposed in a housing hole of the bearing housing and in which a rotational shaft is inserted; and a positioning pin for positioning the floating metal with respect to the bearing housing, the positioning pin being disposed along a radial direction of the rotational shaft. The positioning pin includes a first oil supply hole formed so as to penetrate the positioning pin and communicating with a first space between an inner peripheral surface of the floating metal and an outer peripheral surface of the rotational shaft, and a second oil supply hole formed inside the positioning pin so as to connect a second space to the first oil supply hole, the second space being disposed between an outer peripheral surface of the floating metal and an inner peripheral surface of the housing hole.

The invention claimed is: 
     
       1. A bearing device, comprising:
 a bearing housing; 
 a floating metal having a cylindrical shape and disposed in a housing hole of the bearing housing and in which a rotational shaft is inserted; and 
 a positioning pin for positioning the floating metal with respect to the bearing housing, the positioning pin being disposed along a radial direction of the rotational shaft, 
 wherein the positioning pin includes
 a first oil supply hole formed so as to penetrate the positioning pin and communicating with a first space between an inner peripheral surface of the floating metal and an outer peripheral surface of the rotational shaft, and 
 a second oil supply hole formed inside the positioning pin so as to connect a second space to the first oil supply hole, the second space being disposed between an outer peripheral surface of the floating metal and an inner peripheral surface of the housing hole, 
 
 wherein the bearing housing further comprises a circumferential groove formed on an inner peripheral surface of the housing hole, the circumferential groove forming an annular oil passage disposed on the bearing housing so as to face the outer peripheral surface of the floating metal on an outer peripheral side of the floating metal, and 
 wherein the second oil supply hole of the positioning pin communicates with the second space via the annular oil passage formed by the circumferential groove. 
 
     
     
       2. The bearing device according to  claim 1 ,
 wherein the second oil supply hole opens to the annular oil passage. 
 
     
     
       3. The bearing device according to  claim 1 ,
 wherein the first oil supply hole includes a radial hole portion extending along the radial direction, and 
 wherein the second oil supply hole is connected to the radial hole portion. 
 
     
     
       4. The bearing device according to  claim 1 ,
 wherein the second oil supply hole is formed along a circumferential direction of the rotational shaft. 
 
     
     
       5. The bearing device according to  claim 1 ,
 wherein the bearing housing has a radial hole disposed along the radial direction so as to be connected to the housing hole, 
 wherein the floating metal has a recess recessed inward in the radial direction from the outer peripheral surface of the floating metal, and 
 wherein the positioning pin includes
 a base end portion engaged with the radial hole, and 
 a tip end portion loosely fitted in the recess. 
 
 
     
     
       6. The bearing device according to  claim 5 , further comprising a plug inserted in the radial hole and located outward of the positioning pin in the radial direction,
 wherein the bearing device is configured such that oil is supplied to the first oil supply hole via a space formed between the plug and the positioning pin in the radial direction. 
 
     
     
       7. The bearing device according to  claim 5 ,
 wherein the floating metal has a communication hole formed so as to extend along the radial direction inside the floating metal and open at both ends to a bottom surface of the recess and the inner peripheral surface of the floating metal, respectively, 
 wherein the first oil supply hole is disposed so as to pass through the tip end portion and penetrate the positioning pin along the radial direction, and 
 wherein the first oil supply hole communicates with the first space via the communication hole. 
 
     
     
       8. The bearing device according to  claim 1 , further comprising a locking portion for locking the positioning pin to the bearing housing. 
     
     
       9. The bearing device according to  claim 8 ,
 wherein the locking portion includes
 a male thread formed on the positioning pin at least partially in an axial direction of the positioning pin, and 
 a female thread formed on the bearing housing and mated with the male thread. 
 
 
     
     
       10. The bearing device according to  claim 1 , further comprising at least one thrust collar disposed adjacent to the floating metal in an axial direction of the rotational shaft and configured to rotate together with the rotational shaft,
 wherein the bearing device is configured such that oil is supplied between an end surface of the floating metal in the axial direction of the rotational shaft and the at least one thrust collar via the first space. 
 
     
     
       11. The bearing device according to  claim 1 , comprising:
 an oil inlet formed on an outer surface of the bearing housing and disposed in a region opposite to the positioning pin with respect to the rotational shaft; and 
 a supply passage formed so as to extend along an extending direction of the positioning pin inside the bearing housing, 
 wherein the supply passage is a passage for supplying oil from the oil inlet to the first oil supply hole, and 
 wherein the supply passage is disposed at a position shifted from the positioning pin in an axial direction of the rotational shaft. 
 
     
     
       12. The bearing device according to  claim 1 ,
 wherein the circumferential groove is formed on an entire circumferential region of the internal peripheral surface of the housing hole including a circumferential position opposite to the positioning pin across the floating metal. 
 
     
     
       13. A turbocharger, comprising:
 the bearing device according to  claim 1 ; 
 the rotational shaft rotatably supported by the bearing device; and 
 a compressor impeller and a turbine impeller disposed on the rotational shaft.